The disclosure relates to apparatuses and methods for forming thin glass article, and more particularly to apparatus and methods for forming thin glass articles in an at least partially horizontal direction.
Articles such as electronic devices (e.g., mobile phones, smart phones, tablets, video players, information terminal devices, laptop computer, etc.), architectural structures (e.g., countertops or walls), appliances (e.g., cooktops, refrigerator and dishwasher doors, etc.), information displays (e.g., whiteboards), and automotive components (e.g., dashboard panels, windshields, window components, etc.) incorporate various substrates as internal components or external components. When used in such articles, the substrate can be part of a housing or a display. When used in a display, the substrate may be referred to as a cover substrate and, in some instances, may form part of a touch module. Cover substrates are often transparent and scratch-resistant. Substrates used as housing can form the sides, back and front portions of housing and may exhibit scratch-resistance and opacity, instead of exhibiting transparency.
With continuing efforts to make some articles or components of articles lighter and thinner and to include even greater functionality, substrates, whether used as cover substrates or housing substrates, are becoming thinner (e.g., about 1 mm or less). As substrates become thinner, they are also more susceptible the surface damage that may be imparted on the substrate during processing (e.g., the process steps to provide a thinner substrate). Examples of such surface damage can include thermally or mechanically imprinted scars or marks to the glass substrate when in a molten or viscous form. It has become more important to develop apparatuses and/or methods for providing thin substrates having improved surface quality.
In some applications, the substrate may include glass articles (which may optionally be used as a precursor to glass-ceramics) with specific properties of interest such as low thermal expansion and mechanical strength. In some instances, glass forming methods may be unsuitable as they are not compatible with glasses with the tendency for devitrification (e.g., when the liquidus viscosity is below 50,000 poises). In these instances, the molten glass flow at sufficiently high temperatures and/or low viscosity may be required to avoid devitrification. Alternative glass processes such as rolling may be used; however, known rolling processes are unable to provide a glass article thickness of less than about 2 mm. Moreover, known rolling processes utilize equipment that is vertically oriented, which can require tall processes with costly plant elevation, complex glass article position and speed control along the vertical length and complex separation methods. Accordingly, there is a need for an apparatus and/or process that provides thin glass articles having a thickness of about 1 mm or less, with improved surface quality, made by processes and apparatus having a compact layout.